On the synthesis of pyrazino{[}2,3-b] phenazine and 1H-Imidazo{[}4,5-b]phenazine derivatives

Several pyrazino{[}2,3-D]phenazine derivatives were prepared by the reaction of 2,3-diaminophenazine with different 1,2-diketones. Nucleophilic substitution of 2,3-dibromomethyl-pyrazino{[}2,3-b]phenazine with propanol, morpholine, and potassium thiocyanate gave 2,3-bis(propoxymethyl)-pyrazino{[}2,3-b]phenazine 2,3-bis-(4-morpholinylmethyl)-pyrazino{[}2,3-b]phenazine, and 2,3-bis-(cyanosulfanylmethyl)-pyrazino{[}2,3-b]phenazine. 2-Aryl-1H-imidazo{[}4,5-b]phenazine derivatives were synthesized by a one-pot reaction of 1,3-diaminophenazine with different aromatic aldehydes or acids. Reaction of 2,3-diaminophenazine with acetic anhydride and formic acid afforded 1H-imidazo{[}4,5-b]phenazine and 2-methyl-1H-imidazo{[}4,5-b]phenazine. Chemical and spectroscopic evidences for the product structures of the new compounds are presented.